One of the main problems in the development of devices for mixing and atomization propellants is to provide maximum attainable propellant combustion efficiency—this may be achieved through increase of an area of propellant contact surface and decrease of jet characteristic cross-section size for one of propellants.
Concerning known injector element designs, the realization of the above requirements leads to considerably complicated design.
It is known a coaxial jet injection element having a tip made as a hollow cylinder connecting the liquid oxidizer cavity with combustion zone (combustion chamber interior) and moreover, having a sleeve with cylindrical internal surface that surrounds said tip providing clearance and connecting the gaseous fuel cavity with combustion zone (V. E. Alemasov et al.: “Theory of rocket engines”—Textbook for students acquiring machine-building specialization in higher education centers, Moscow, Publishing House “Mashinostrojenie”, 1980, FIG. 18.2, pp. 225–226).
The oxidizer in this injection element is supplied into the combustion zone through the axial channel in the tip interior while the fuel is supplied through the annular gap between the said sleeve and the said tip. The oxidizer jet at the injection element outlet has the form of solid cone directed with its vertex toward the injection element tip, while the fuel jet has the form of hollow cone. The fuel-oxidizer contact takes place on the surface of the solid cone. Such supply scheme doesn't provide due quality of propellants spraying—this lowers the coefficient of propellant combustion efficiency and, as a consequence, leads to losses of the thrust specific impulse value.
It is known the powder coal burner comprised of a body with injection ports in the lateral surface, comprising moreover a conical insert placed in front of the said ports, this conical insert having a conical corrugated extension mounted with provision of annular gap between the said extension and the said conical insert with axial displacement of the said extension, and the number of corrugations of the said extension is equal to the number of the ports in the body, the corrugation peaks being directed towards the said body central line and positioned in front of respective ports (Cert. of invention, SU 1320593).
It is known a burner containing a tube connected with a gas source, the said tube having an outlet nozzle with radial longitudinal grooves in its wall, the said wall has longitudinal corrugations forming the said grooves. The forward end faces of the corrugations are located on the cone generating line having the 45–180° angle inside nozzle (Cert. of invention, SU No. 909432).
It is known a burner with a tube and an outlet nozzle having radial grooves in its wall (SU497650).
It is known an open injector for internal combustion engine, having the said injector the improved form of sprayer outlet orifice that influences upon the propellant jet form in dependence of the propellant supply flow rate. The said injector provides reliable inflammation and full combustion of the working mixture due to that the injector orifice has an expanding towards the outlet grove, and the form of the said opening is preferably linear or curvilinear that gives asymmetry to the exit cross-section.
The said opening may have oval, rectangular or round form in cross-section or the form of two contiguous circumferences (patent application FR No. 2420038 of 16.03.78).
The main disadvantage of the above mentioned devices is the low value of mixture formation completeness. This leads to incomplete combustion of propellants and reduced efficiency.